1. Field of the Invention
The present invention relates to a process for producing a liquid ejection head for ejecting a liquid such as an ink to conduct recording operation as well as a liquid ejection head.
2. Description of the Related Art
A liquid ejection head used in liquid ejection apparatus represented by an ink jet recording apparatus has heretofore been provided with a recording element substrate 1, a flow path 5 and a support member 6 as illustrated in FIGS. 5 to 6B. The recording element substrate 1 is provided with an ink ejection orifice, and the support member 6 has the flow path 5 for supplying an ink. Silicon is generally used as the recording element substrate 1, and the support member 6 is made of a resin.
As illustrated in FIG. 5, a method of bonding and fixing the recording element substrate 1 with an adhesive 2 is used as a method for fixing the recording element substrate 1 on to the support member 6. The adhesive is applied by a method such as dispensing or transferring methods.
Here, a color recording element substrate 1 having a plurality of flow paths 5 is considered in particular. The adhesive 2 is pressed against a back surface of the recording element substrate 1 and spread when the recording element substrate 1 is bonded and fixed. It is necessary to control the height of the adhesive 2 so as not to excessively narrow the flow paths 5 due to squeeze-out of the adhesive. If the height of the adhesive at respective parts is uneven, there is a possibility that adhesion failure may occur to leak the adhesive 2 to an exterior or an interior (between color separation walls).
Japanese Patent Application Laid-Open No. 2006-212902 discloses a method for keeping a pattern right after application of an adhesive by providing a V-shaped groove in an adhesive application portion of a support member 6 so as to make it possible to apply a small amount of the adhesive with an even height and to prevent the spread of the adhesive.
Even when the application height of the adhesive is stabilized according to the method disclosed in Japanese Patent Application Laid-Open No. 2006-212902, however, leakage to the exterior may occur in such a situation as illustrated in FIG. 5 in some cases. Since the support member 6 is molded from a plastic, there is a production limit to the narrowing of the width of a color separation wall 4. In addition, it is necessary for the flow path 5 to surely have a certain width from a viewpoint of bubble-releasing ability (width necessary to naturally release a bubble in an ink).
There is a limit to the narrowing of the widths of the color separation wall 4 and flow path 5 for their respective reasons. However, the recording element substrate 1 bonded and fixed on to the support member 6 tends to narrow its width 20 for the purpose of reducing the cost rate of the resulting head. As a result of the development of this narrowing technology, a possibility that such an outer leakage defect 21 that an outer portion of the recording element substrate 1 comes into no contact with the adhesive 2 as illustrated in FIG. 6B may occur has emerged. Here, FIG. 6B is a sectional view taken along line 6B-6B in FIG. 6A.
The outer leakage defect 21 can be suppressed when a squeezed amount of the adhesive 2 is increased. However, the adhesive 21 squeezed out narrows the flow path 5 if the adhesive 21 is over squeezed, so that the squeezed amount of the adhesive cannot be increased more than a certain amount taking into account the bubble-releasing ability. Accordingly, there is a demand for ensuring adhesion at the outer portion by another method for producing a liquid ejection head without causing leakage to the exterior.